Enantioselective Direct Aldol-Tishchenko Reaction: Access to Chiral Stereopentads
摘要:
The aldol-Tishchenko reaction of aromatic aldehydes in the presence of titanium(IV) tertbutoxide and amino alcohols is described. When used with cinchona alkaloids, stereopentads were isolated for the first time with a high degree of diastereo- and enantioselectivity.
A catalyticasymmetricaldol reaction of alkenyl trichloroacetates with aldehydes was achieved using dibutyltin dimethoxide and BINAP · silver(I) complex as catalysts in a mixed solvent consisting of THF and MeOH. Various optically active β-hydroxy ketones were diastereoselectively obtained not only from aromatic and α,β-unsaturated aldehydes but also from an aliphatic aldehyde with good enantioselectivity